This invention concerns compositions for forming peelable films. More precisely, it concerns curable organopolysiloxane compositions for forming peelable films which can be lightly peeled from adhesive substances and which are stable with time.
It is known that organopolysiloxane compositions which cure by condensation or addition reactions can provide for a base material the property of peelability from adhesives substances by forming curable films on the surface of base materials, such as various types of papers, synthetic films, natural and synthetic fibers and glass fabrics. These compositions are widely used in applications such as labels, tapes, processed papers and packages for asphalt and pitch.
Curing by an addition reaction is superior to curing by a condensation reaction because the application conditions minimally affect the application time and the productivity of the former is higher because the curing rate is faster. In terms of the peeling efficiency, the peeling resistance of the former system is low and its peeling rate is relatively unaffected by external conditions. Thus, the former system has recently come to be utilized in a variety of fields.
However, problems with an addition reaction system arise more easily during processing due to static electricity. In addition, the peeling efficiency of processed peelable papers is unstable due to the effects of the atmosphere. If labels and tapes are processed using peelable papers which have been exposed to the atmosphere, the initial peeling resistance is high and increases with time. If certain adhesives are used, the paper cannot be peeled at all.
The application of common hydrocarbon anti-electrostatic agents not only causes a decline in the peeling efficiency, but also cause a large decline in adhesion to the above-mentioned bases. Thus, the application of such an agent is impractical. The inventors investigated methods for overcoming the above-mentioned drawbacks.